let arr = [ 1, 2, 3, 'aa', 'lucy'];
console.log(arr.toString());
// 1,2,3,aa,lucy

let objArr = [
  { name: 'zg', age: 18 },
  { name: 'kobe', age: 35 },
];
console.log(objArr.toString());
//[object Object],[object Object]

